Talks

This course is aimed at advanced undergraduate and beginning graduate students, and is inspired by a book by the same title, written by Padmanabhan. Each session consists of solving one or two pre-determined problems, which is done by a randomly picked student. While the problems introduce various subjects in Astrophysics and Cosmology, they do not serve as replacement for standard courses in these subjects, and are rather aimed at educating students with hands-on analytic/numerical skills to attack new problems.

This course is aimed at advanced undergraduate and beginning graduate students, and is inspired by a book by the same title, written by Padmanabhan. Each session consists of solving one or two pre-determined problems, which is done by a randomly picked student. While the problems introduce various subjects in Astrophysics and Cosmology, they do not serve as replacement for standard courses in these subjects, and are rather aimed at educating students with hands-on analytic/numerical skills to attack new problems.

I will report on efforts to implement a new method for simulating concatenated quantum error correction, where many levels of concatenation are simulated together explicitly. That is, the approach involves a Monte Carlo simulation of a noisy circuit involving many thousands of qubits, rather than tens of qubits previously. The new approach allows the threshold and resource usage of concatenated quantum error correction to be determined more accurately than before. Also, the approach makes it possible to better study the effects of circuit optimizations and message-passing algorithms [Poulin, PRA, 2006] on the performance of fault-tolerant concatenated quantum error correction. Such studies are necessary in order make a proper comparison with competing families of error-correction protocols, such as those involving surface codes. In the talk, a range of new numerical results will be presented.

We will discuss the missing pieces in the understanding of the effective field theory description of string creation, the T-dual of the Hanany-Witten effect, both in the open and closed string picture. We explain the origin of the \'bare\' Chern-Simons term, so far added in by hand. There however remain unsettled issues concerning the need to modify the DBI action and the interpretation of this term in M-theory.

The idea behind the \'Open Science Movement\' is that by making data, results, and protocols freely available to the research community for use and re-use a step change in the efficiency of carrying out science can be achieved. In this talk I will discuss the experience of my research group in pursuing \'Open Notebook Science\' in which we make our laboratory notebooks freely available on the web as experiments are recorded. This involves both the development and use of new tools to make the recording process practical and useful and the cultural challenges of convincing other scientists that this is a worthwhile, and not completely foolhardy, approach.

Computation is increasingly important in all branches of science, but most scientists have no idea how reliable their software is, and cannot reproduce even their own computational results if more than a few weeks have passed. \'Live on the web\' labs and other new ideas promise to change this, but face an uphill battle against entrenched practices and institutional lethargy. This talk looks at how we got into this mess, what could get us out of it, and how likely scientists are to actually embrace change.

How can we best take advantage of the internet to improve how science is done? Much attention has been paid to open access and open data as enablers of online innovation. In this talk, I discuss the complementary issue of cultural openness in science, and argue that a relatively closed culture is inhibiting online innovation in science. I\'ll discuss ways this culture may be changed, and what opportunities may result.

Three revolutions are coming together to shift people\'s social lives away from tight-knit family and neighborhood relationships towards more far-flung, less tight, more diverse personal networks. The internet revolution, the mobile revolution, and the social network revolution are producing a new societal reality we call \'networked individualism.\' Analysts argue over whether this leads to social decay or utopia; we argue instead that social change is occurring that has both benefits and drawbacks. We use evidence from the Pew Internet and American Life project and the Connected Lives project to document key aspects of the transformation: Communication is from and to the person. This is a major change from situations when the household, the village or even the urban neighborhood were the major source of connectivity. For better or worse, people are connected as networked individuals. This means they have community, but it is less palpable than the organized groups of the past. People don\'t live online. Rather, they integrate a variety of communication media to stay connected - in-person encounters, formal meetings, phone calls by landline and mobile phones, emails, instant messaging, and more public Web 2.0 activities, such as listservs, social network sites, and blogs. Many of the minority who say they are not directly on the internet use it anyway, with their family and friends communicating and seeking information for them. Households are networks, not groups. Household members are in frequent contact, but not necessarily getting together as a solidary group. These are smaller households than in past decades, often with only one parent and often with no or only one child. Household members communicate in a variety of ways - hugs in passing, post-it notes, mobile phoning, and email. What they don\'t do is sit down and have family dinners every night or stay together on weekends. Relationships in the wider world are built around looser, rather than denser network groupings. Among other things, this means that people have a variety of social ties to count on, but not one sure-fire community home. Unlike people\'s lives in Pleasantville, they don\'t have the security of one big happy community. But they also escape the social control that comes from being in a densely-knit, bounded community. In these networks, people have more uncertainty, but also more maneuverability. People are their own switchboards, making, maintaining and breaking ties. Rather than sitting back and letting Mom or Sis take care of their networks, they must work more actively on maintaining each tie separately. People rely on multiple specialized relationships, rather than a few all-encompassing relationships. They access different parts of their networks to solve certain problems and to gain social support. They must shop in specialized boutiques for help instead of turning to close friends and family who, like a general store, provide all sorts of help People have partial membership in multiple networks and rely less on permanent memberships in settled groups. In this environment, people must deal with frequent turnover and change in their friendships, and they must be forever calculating where they can turn for different kinds of help. People have more long-distance relationships and more transitory relationships than in the past. While they still have neighbors, neighbors are only a small portion of their interpersonal lives. As a result, their life routines are different from the lives that their parents or grandparents led. They are traveling more by car and plane to see friends and relatives; and they are spending much more time using the internet and mobile phones to socialize with distant ties. The internet, mobile chatter, and in-person contact are in constant interplay in people\'s lives. Most still meet in person, and continue contact in between meetings via the internet. People expend new energy and effort to manage their networks through electronic and mobile connectivity. They also hyper-coordinate their schedules by using mobile phones to plan gatherings. Those who first meet online usually arrange to get together in person. People\'s networks are now larger. While the number of their strong ties - socially close relationships with friends and relatives - has stayed about the same, they have greater numbers of weaker ties. They have more \'friendsters\' than friends. Yet such weak ties can help them at times with crucial elements of information, sociability and support - e.g. as they seek jobs, cope with health issues, and make purchase decisions. People\'s work lives are built around more creative jobs rather than manufacturing or standardized paper pushing. This means that they have more reporting relationships and fewer hierarchical relationships. They typically work in multiple teams, rather than with one boss. They rely heavily on the internet, within-organization intranets, and mobile phones to obtain and share information. People now can obtain information from a greater variety of sources and are heavily using the internet for that purpose. This diversity both empowers people - they no longer need rely on \'the experts\' - but it also creates uncertainty about whom and what to trust. The result is that people cycle back and forth between the internet and dialogue with their friends - using in-person conversations, phone chats and emails to exchange opinions. People can now use the internet and other digital tools to create and contribute information to public discourse. They can do so with considerably greater ease and impact than in the past. This allows them to build new branches on their networks as they contribute to knowledge, conduct conversations, and rate/rank/review the content created by others. These social changes are consequential in their own right, but they especially matter because people rely on their social networks more than in the past to help them learn things, assess options, make decisions, and solve problems. The explosion of information and communication sources has pushed people onto the path of greater involvement with their extended networks of people as they negotiate the complexity of modern life. At the same time, it has increased the potency of those who are active and important in their networks - who bridge different social circles, advise people, and help them to connect with each other.

This course is aimed at advanced undergraduate and beginning graduate students, and is inspired by a book by the same title, written by Padmanabhan. Each session consists of solving one or two pre-determined problems, which is done by a randomly picked student. While the problems introduce various subjects in Astrophysics and Cosmology, they do not serve as replacement for standard courses in these subjects, and are rather aimed at educating students with hands-on analytic/numerical skills to attack new problems.